Malware is a collective term for malicious software programs used by hackers and cybercriminals to exploit vulnerabilities in a computer or network. It is dangerous and stealthy, often infecting a computer unbeknownst to the user and sometimes under the nose of an anti-virus program without sufficient detection.

Early malware experiments were primitive. They spread locally through floppy disks. But as the internet and networking became a thing, authors started to develop self-replicating programs that could hop from host to host. These were written to crash computers, bring down networks and wreak havoc. Today’s malware is even more sinister, with the capability to spy on you, steal your data and even hold you for ransom.

Where does it come from?

Malware can infect a computer from a variety of different sources. These include dodgy downloads from email attachments, downloading content from file sharing sites and torrents, removable media like USB sticks, SD cards and flash drives, trojan horses (fake software that masquerades as legitimate software), other computers on the same network if there are security vulnerabilities, and dodgy websites (especially porn and gambling sites) that can infect a browser with adware and toolbars.

In the vast majority of cases, malware infects a computer as a result of the user downloading malicious software or content. This is why it is so successful, because there is often no way to tell a file is malicious before it’s downloaded.

What’s the risk?

Malware isn’t a good thing to have. The consequences of an infection depend on what type of malware it is and how aggressive it is. Risks include being hacked, your personal, sensitive and financial information being stolen, your computer being held for ransom, your computer being used as part of a botnet to conduct mass illegal activity, your sessions being tracked, your screen being watched, your files and system being corrupted, modified or deleted, your computer being taken over remotely, your internet bandwidth being eaten up, your computer infecting other machines, and your computer infecting entire networks.

What are the different types?

Because ‘malware’ is a catch-all for any malicious software, there are various different types. Some are relatively harmless programs while others are destructive and dangerous.

Adware

Adware pushes advertisements onto your computer screen usually in the form of pop-ups in a web browser but also through software on a desktop.

Bot

A bot hides itself in a computer and can use that computer’s resources to carry out tasks, such as a DDoS attack, as a cog in the wheel of a larger botnet.

Bug

A bug is a flaw in a software program that results in an undesirable outcome, such as a computer crashing, freezing or rebooting randomly.

Ransomware

Ransomware holds a computer for ransom. It does so by locking down the hard drive or encrypting files. It can also be used to facilitate cybertheft or sabotage.

Rootkit

A rootkit remotely accesses and controls a computer covertly. It can be used to steal information, alter software, install other types of malware and even modify system files.

Spyware

Spyware spies on a computer user’s activity and can record a session in its entirety, including keystrokes, program usage and browsing history.

Trojan horse

A trojan horse is a software program that disguises itself as the real thing, thus tricking users into downloading and installing malware.

Virus

A virus can be written to steal information and implant bots, adware and spyware. It can damage files and spread itself from computer to computer over a network.

Worm

A computer worm can steal data, delete and modify files, add the host machine to a botnet and significantly reduce computer performance by eating up resources.

What are the symptoms?

Malware can affect your computer in a number of different ways. When it is executed, it tends can eat up computer resources (high CPU usage) and eat up internet bandwidth (slow internet). Your computer can crash, freeze or perform oddly.

You may discover your files are being modified or deleted, or even new files being created that you swear blind you never created yourself. Programs can reconfigure themselves, refuse to open or respond poorly. Your antivirus and firewalls may not function properly or be disabled.

The appearance of your desktop may change. You may see ad pop-ups in your web browser or on your desktop. You may experience problems connecting to a network or even problems connecting devices to your computer. Some malware can tap into Outlook or other email applications and send out spam.

How do I protect myself?

The best defence against malware is to recognise where it comes from and adapt your online behaviour to minimise your activity at these touchpoints. Be careful about what software you download (the same goes for media), don’t open strange email attachments unless they have been scanned by an anti-virus/malware program, don’t click pop-up ads, close suspicious windows, and stay away from dodgy sites.

Fact is, most malware infections occur because of bad online habits. Stamping these out will reduce your exposure to malware in the first place.

It is also essential you install and maintain an anti-virus and anti-malware program to protect your computer. Security software with real-time protection is a must if you want to keep your computer clean. Webroot for PC / MAC is a complete anti-virus and malware security suite with always-on virus protection and ransomware protection. It can secure your PCs or Macs to keep your network safe.

It is not advisable to run your computer without an anti-virus or anti-malware program, nor is it advisable to only run with a disinfection tool. Disinfection tools are only effective at removing malware and will not prevent your computer from being infected in the first place. If malware is highly aggressive, it may not allow a disinfection tool to run at all, which means you may be blocked from downloading or running anti-malware.